Alternative medicine are whole medical systems that did not fit with conventional medicine as they have completely different philosophies and ideas on the causes of disease, methods of diagnosis and approaches to treatment. Although often overlapping, complementary medicine (or therapies) are specifically defined as those that can be used alongside conventional medicine. The term complementary and alternative medicine (CAM) include both approaches. <!--LGfEGNT2Lhm-->Integrated medicine is a new hybrid of conventional and complementary therapies.

One of the most commonly used definitions is that used by the Cochrane Complementary Medicine Field;

“Complementary medicine includes all such practices and ideas which are outside the domain of conventional medicine in several countries and defined by its users as preventing or treating illness, or promoting <!--LGfEGNT2Lhm-->health and well being. These practices complement mainstream medicine by 1) contributing to a common whole, 2) satisfying a demand not met by conventional practices, and 3) diversifying the conceptual framework of medicine. ” (Berman 2006)

CAM is controversial because of the evidence that it works, and how it works. There have been several attempts to estimate the amount of money available to CAM research as compared to conventional medical research and current estimates suggest that CAM research represents less than 0.01% of the current UK medical research budget. Anecdotal evidence is very strong, but clinical trials are complicated in this area by the holistic approach and the use of placebo controls.